Background: The use of functional and/or cognitive assessment in the emergency department (ED) to inform decision making in the complex older adult is considered important, yet not routinely administered. Method: Electronic databases were searched to identify eligible published research studies: older adults >65 years; the administration of a functional and/or cognition assessment instrument whilst the older adult is in any part of the ED; interventions resulting from the administration of the instrument; and a measured outcome post ED visit. A revised scoping review methodology was applied to chart study data and to identify key differences. Results: Ten research studies were identified that met the criteria for review. There are a variety of assessments, aimed at different age groups, for several purposes and used at different times in the ED journey. Assessments are not being used in conjunction with routine medical assessment early in the ED patient journey. Conclusion: This scoping review identified no consistent suite of tools being administered in the ED to influence the disposition decision with measurable outcomes. Further research is required to identify a suite of assessment instruments suitable for use in the ED setting aimed at improving disposition decision making in the complex elderly person.